This is largely a matter of habit, in the sense of repeated effort and repeated exercise of will power.

If the man has the right stuff in him, his will grows stronger and stronger with each exercise of it--and if he has not the right stuff in him he had better keep clear of dangerous game hunting, or indeed of any other form of sport or work in which there is bodily peril.
After he has achieved the ability to exercise wariness and judgment and the control over his nerves _which will make him shoot as well at the game as at a target_, he can begin his essays at dangerous game hunting, and he will then find that it does not demand such abnormal prowess as the outsider is apt to imagine.

A man who can hit a soda-water bottle at the distance of a few yards can brain a lion or a bear or an elephant at that distance, and if he cannot brain it when it charges he can at least bring it to a standstill.

All he has to do is to shoot as accurately as he would at a soda-water bottle; and to do this requires nerve, at least as much as it does physical address.

Having reached this point, the hunter must not imagine that he is warranted in taking desperate chances.